Discharge tube spacer



De 16, 1941. A, Q ROCKWQOD 2,266,080

I DISCIINYEy TUBE SPACER Filed 21mg. 17, 1940 oo noon a N oouooooncooa oo an.:

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Patented Dec. 1.6,. 1941 UNITED STATES DISCHARGE TUBE SPACER Alan C. Rockwood, Newton, Mass., assignor to Raytheon Production Corporation,

Newton,

Mass., a corporation of Delaware Application August 17, 1940, Serial No. 353,108

(Cl. Z50-27.5)

6 Claims.

This invention relates to an electrical space discharge tube of the vacuum type in which the dimensions of the tube are reduced to relatively small value. In such a tube the problem of mounting the various tube elements on the usual insulating spacer presents various difficulties because of the small space available.

An object of this invention is to devise a novel insulating spacer with which the tube elements may be readily assembled.

Another object is to simplify the assembly and manufacture of tubes of small size.

The foregoing and other objects will be best understood from the following description of an exemplication thereof, reference being had to the accompanying drawing, wherein:

Fig. 1 is a cross-section of my novel tube taken along line I-I of Fig. 3;

Fig. 2 is a right-hand view of the electrode assembly shown in Fig. 1 with the glass envelope shown in cross-section;

Fig. 3 is a top view of the electrode assembly of Fig. 1; and

Fig. 4 is an enlarged portion of one of `the insulating spacers showing a detail thereof.

The tube illustrated contains an electrode assembly consisting of an anode I, a lamentary cathode 2, and a plurality of grids 3, 4 and 5. The grids are wound upon and supported by grid side rods 6 6, 'I-l and 8 8, respectively. Proper spacing and support of the electrodes are provided by upper and lower insulating spacers 9 9, preferably of mica. The spacers 9-9 are cut away to provide resilient projections I which are adapted to resiliently engage the inner wall of the glass envelope. The spacers 9 are each provided with' a triangular` slot I I having a rectangular recess I2 in the base thereof in order to receive and support one of the side rods 6 of the grid 3. y i

The lamentary cathode 2 is retained in the apex of each of the triangular slots I I. In order to support the lower end of the fllamentary cathode 2, a U-bracket I3 is secured to the lower spacer 9 and projects from the lower side thereof. The bracket I3 has welded thereto a tab I4 which in turn is welded to the lower end of the filamentary cathode 2, and serves as a mechanical support and electrical connector therefor. A conducting spring member I5 is welded at one end to the upper end of the lamentary cathode 2, and at its other end to one of the side rods 8 of the grid 1. The spring I5 pulls upwardly on the lamentary cathode 2, and maintains the proper jects beyond the apex of the upper triangular slot I I so as to force the upper end of the lamentary cathode into the apex of said triangular slot. Likewise the tab I4 is located beyond the apex of the lower triangular slot II so as to maintain the lower end of the filamentary cathode in said apex.

The anode I is provided with a plurality of tabs I6 at its upper edge and aplurality of tabs I1 'at its lower edge. 'These tabs are bent over onto the upper and lower surfaces of the upper and lower spacers 9, respectively, and serve to main- Iain th'e electrode assembly in its assembled form, whereby it may be readily handled as a unit before insertion into the glass envelope. As an additional means for retaining the grid 5 in place within the electrode assembly, one of the side rods 8 may be provided with stops I8I8 welded to the upper and lower ends of said side rod and bearing against the upper and lower faces of the upper and lower spacers 9, respectively.

In order to provide for an external electrical connection to the anode I, a connector I9 is welded to one of the lower tabs I1 and also to a lead-in conductor 20. Lead-in conductors 2l, 22, 23 and 24 are also provided for the electrodes 2, 3, 4 and 5, respectively. For this purpose the y .lead-in 2| is welded to the bracket I3, th'e lead-in 22 is welded to one of the side rods 6, the lead-in 23 is welded to one of the side rods l, and the lead-in 24 -is welded to one of the side rods 8. A ring 25 of getter material may be conveniently supported on the electrode -assembly by being welded to the upper end of one of the side rods 8.

The triangular slot and rectangular recess I2 in the upper and lower insulating spacers greatly facilitate the assembly of the tube structure, particularly in the small dimensions available. For example, the tab I4 of the filament 2 can readily be threaded th'rough the combined opening, whereas if the triangular slot I I alone were avail- A able, such threading would be relatively difficult.

tension th'ereon. Furthermore, said spring pro- 55 Also due to the combined arrangement of the openings II and I2, the side rod 6 of the grid 3 can readily be assembled therein despite the close spacing. Also the combined opening is easier to fabricate in insulating spacers of the comparatively small area which must be used in tubes of this kind.

In order to eliminate vibration of the filament, a spring wire 26 is provided. One end of this spring wire is welded to a tongue 21 formed in the side wall of the anode I by cutting a U-shaped slot therein. The spring wire 26, except for the point at which it is welded to the tongue 2l, is

covered with an insulating coating 28 bearing against the filament 2. Any tendency for vibration to occur is absorbed by the spring wire 28 and the insulating coating 28 thereon.

The above electrode assembly is inserted as a unit within a straight-sided glass tube 29. The lower end of this tube is heated and softened suinciently so that it may be pressed to make the press or seal 30. The upper end of the tube 29 is provided with the usual tubulation, exhausted and sealed oi at 3|.

Ot course it is to be understood that this invention is not limited to the particular details as described above as many equivalents will sug gest themselves to those skilled in the art. For example, the invention can be applied to tubes of other types in which other numbers of grids might be used. Various other changes embodying the teachings of this invention will suggest themselves to those skilled in the art. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. A spacer for an electrical space discharge tube comprising an insulating plate, a triangular opening therein, and an additional restricted opening in said spacer extending from the base of the triangle.

2. A spacer for an electrical space discharge tube comprising an insulating plate, an opening therein having an angular recess, and an additional restricted opening in said spacer extending from said rst-named opening opposite said angular recess.

3. A spacer for an electrical space discharge tube comprising an insulating plate, a triangular opening therein, and a substantially rectangular recess therein extending from the base oi the triangle.

4. An electrical space discharge tube assembly comprising a lamentary electrode, an additional electrode having a side rod, and an insulating spacer for said electrodes, said spacer having a triangular opening therein, said lament being supported in the apex of the triangle, and an additional recess in said spacer extending from the base of the triangle, said side rod being supported in the bottom of said additional recess.

5. An electrical space discharge tube assembly comprising a illamentary electrode, an additional electrode having a 4side rod, and an insulating spacer for said electrodes, said spacer having an opening therein having an angular recess, said lament being supported in the apex of said angular recess, andan additional recess in said spacer extending from said first-named opening opposite said angular recess, said side rod being supported in the bottom of said additional recess.

6. An electrical space discharge tube assembly comprising a lamentary electrode, an additional electrode having a side rod, and an insulating spacer for said electrodes, said spacer having an opening therein having an angular configuration at one side thereof, said lament being supported in the apex of said angular conguration, said opening being congured to receive said side rod opposite said angular configuration, said side rod being supported in the latter coniiguration.

ALAN C. ROCKWOOD. 

